WASHINGTON--(BUSINESS WIRE)--April 3, 2006--Plexxikon Inc. today announced that the company has initiated IND-enabling studies with PLX4032, the company’s oncogenic B-Raf inhibitor, a novel, small molecule drug candidate for the treatment of cancer. This compound selectively inhibits the cancer causing form of the B-Raf gene, a mutation found in 70% of skin cancers and a significant number of colorectal, ovarian and thyroid cancers. At the 97th Annual Meeting of the American Association for Cancer Research, Plexxikon scientists presented preclinical data demonstrating that a low dose of this oral V600E B-Raf inhibitor preferentially stopped tumor growth in malignant melanoma and colorectal cancer cells.